The purpose of this study is to determine whether improvement in fat and muscle metabolism
after the treatment with Omacor (fish oils) provides insight into the link between obesity,
fat and muscle function leading to metabolic syndrome, which is a risk factor for heart
disease and diabetes.
The development of type 2 diabetes (T2DM) represents a complex series of events, involving
abnormalities in adipose tissue lipid distribution and insulin action. Along with an increase
in adipose tissue mass is an increase in inflammation brought about by macrophages that
infiltrate adipose tissue. These macrophages express inflammatory cytokines such as TNF- and
IL-6, which are correlated with insulin resistance and metabolic syndrome, and suggest that
metabolic syndrome and diabetes are conditions characterized by a state of chronic, low-grade
inflammation. Thiazolidinediones (TZDs) improve insulin sensitivity via activation of PPAR- ,
and there is much evidence that PPAR agonists also have anti-inflammatory properties.
Fish oils are rich sources of Omega-3 fatty acids and there is a large literature on the
potential benefits of fish oils on lowering serum triglycerides, cardiovascular protection,
and immune modulation, and there is evidence that fish oils also activate PPAR . Hence, the
focus of this study will be on subjects with insulin resistance and metabolic syndrome, but
who do not yet have diabetes. We plan to treat insulin resistant subjects with fish oils and
ask the following questions.
Hypothesis 1. The treatment of insulin resistant subjects with fish oils will reduce adipose
Aim 1. From blood samples drawn before and after treatment, we will measure levels of
circulating inflammatory cytokines.
Aim 2. Adipose tissue biopsies will be performed before and after fish oil treatment. From
the adipose biopsies, we will quantitate cytokine expression, macrophage number, and we will
look for evidence of macrophage apoptosis.
Aim 3. We will determine whether fish oil treatment increases the adipose tissue secretion
and serum level of the high molecular weight form of adiponectin.
Hypothesis 2. The reduction in inflammatory markers occurs through an activation of PPAR by
the fish oils.
Aim 4. Adipose tissue and macrophages will be treated in vitro with fish oils in the presence
and absence of a PPAR inhibitor. We will determine whether fish oils stimulate the secretion
of the high molecular weight adiponectin isoform from adipose tissue and whether they induce
apoptosis from macrophages, and whether this process is inhibited by the PPAR inhibitor.
Hypothesis 3. Fish oils improve peripheral insulin sensitivity through a reduction in
intramyocellular lipid, and an improvement in muscle insulin signal transduction.
Aim 5. Before and after treatment with fish oils, insulin sensitivity will be measured, along
with intramyocellular lipid and genes involved in insulin action and muscle lipid oxidation.
- BMI 27-45 kg/m2
- age 35-65 years
- abnormal carbohydrate metabolism
- triglycerides over 700 mg/dl
- renal disease
- liver disease
- congestive heart failure
- history of heart disease or stroke
- chronic aspirin or NSAID use (anti-coagulant)
- history of a bleeding disorder
- use of statins, fibrates, ACE inhibitors, angiotensin II receptor blockers and
- diet heavy in omega-3 fatty acids (salmon, sardines, flaxseeds)